The invention relates to novel bis(perfluoro-n-alkane-sulfonates) of the formula I: 
where
n is 3, 4, 5, 6, 7, 8 or 9, 
where nonadjacent groups xe2x95x90CRxe2x80x94 may be replaced by xe2x95x90Nxe2x80x94, and xe2x80x94CHRxe2x80x94 may be replaced by xe2x80x94NRxe2x80x94, xe2x80x94Oxe2x80x94 or xe2x80x94Sxe2x80x94 and
R is alkyl or alkoxy having from 1 to 12 carbon atoms, halogen, xe2x80x94CN, xe2x80x94CF3, xe2x80x94OCF3 or unsubstituted phenyl or phenyl which is monosubstituted or polysubstituted by alkyl or alkoxy having from 1 to 12 carbon atoms, halogen or xe2x80x94CN, where if more than one R is present the substituents R may be identical or different.
The invention also relates to a process for preparing the bis(perfluoro-n-alkanesulfonates) of the formula I and their use as precursors for the preparation of chiral phosphine ligands for transition metal catalysts.
Chiral phosphine ligands such as 2,2xe2x80x2-bis(diphenylphosphino)-1,1xe2x80x2-binaphthyl (BINAP) and analogous phosphines are of great importance as constituents of transition metal catalysts used in enantioselective hydrogenations or CC couplings. Various ways of preparing these phosphines are known in the literature. In general, these start from the corresponding binaphthols or analogous phenol derivatives whose hydroxy groups are converted into leaving groups and subsequently replaced by phosphine groups.
U.S. Pat. No. 5,399,771 discloses a process for preparing BINAP starting from enantiomerically pure binaphthol which is firstly converted into the corresponding bis(trifluoromethanesulfonate). BINAP is subsequently obtained by nickel-catalysed coupling with diphenylphosphine. Disadvantages of this process are the high price and the difficulty of industrial handling of the sensitive and extremely aggressive trifluoromethanesulfonic anhydride in the preparation of binaphthol bis(trifluoromethanesulfonate). The use of other trifluoromethanesulfonic acid derivatives such as trifluoromethanesulfonyl fluoride or chloride is also difficult in process engineering terms due to the high volatility of the compounds (b.p.=xe2x88x9220xc2x0 C. and 32xc2x0 C., respectively).
It is an object of the invention to provide a process which can be carried out industrially, does not have the abovementioned disadvantages and makes it possible to obtain, inexpensively and technically simply, compounds which are suitable as starting substances for the synthesis of chiral and phosphine ligands for transition metal catalysts.
It has surprisingly been found that the compounds of the formula I can be obtained in a simple manner by reacting the respective phenols with the corresponding perfluoro-n-alkanesulfonyl fluorides, chlorides or anhydrides and that significantly improved yields in the preparation of phosphine ligands for transition metal catalysts are obtained by use of the compounds of the formula I.
The corresponding relatively long-chain perfluoroalkanesulfonyl fluorides, chlorides or anhydrides are commercially available at favourable prices or can easily be prepared by known methods (e.g. DE 1912738, DE 42118562).
The invention accordingly provides bis(perfluoro-n-alkanesulfonates) of the formula I: 
where
A, B and n are as defined above.
The invention further provides a process for preparing the bis(perfluoro-n-alkanesulfonates) of the formula I, characterized in that compounds of the formula II 
where A and B are as defined above are reacted with the corresponding perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride in the presence of a base.
The bis(perfluoro-n-alkanesulfonates) of the formula I prepared from the phenols of the formula II by the process of the invention are, in particular, valuable intermediates for the synthesis of chiral catalysts such as 2,2xe2x80x2-bis(diphenylphosphino)-1,1xe2x80x2-binaphthyl (BINAP) and analogous compounds.
A is preferably 
B is preferably xe2x80x94(CHR2)4xe2x80x94 or 
in particular 
n is preferably 3, 4, 5 or 7, in particular 3 or 7. n is very particularly preferably 3. R is preferably alkyl or alkoxy having from 1 to 7 carbon atoms, F, Br, CN, xe2x80x94CF3, xe2x80x94OCF3, in particular xe2x80x94CH3, xe2x80x94OCH3, CN or xe2x80x94CF3.
If R in the formulae above and below is an alkyl radical or an alkoxy radical, this may be linear or branched. It is preferably linear and has 1, 2, 3, 4, 5, 6 or 7 carbon atoms, and is thus preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, also octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.
The radical R can also be an optically active organic radical having an asymmetric carbon atom.
Above and below, halogen is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine. Halogen is particularly preferably fluorine or bromine.
Perfluoro-n-alkanesulfonates of the component formulae I1-I13 are particularly preferred embodiments of the invention.
where R and n are as defined above and R1 is alkyl or alkoxy having from 1 to 3 carbon atoms, F, Br, CF3 or CN.
Very particular preference is given to the compounds of the formulae I1, I2, I3, I7 and I8.
The reaction procedure of the process of the invention for preparing the compounds of the formula I is simple, with the corresponding phenol derivative of the formula II being reacted with the corresponding perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride at temperatures of from xe2x88x9230xc2x0 C. to +70xc2x0 C., preferably from xe2x88x9210xc2x0 C. to +50xc2x0 C., in particular from 0 to 30xc2x0 C., under superatmospheric or subatmospheric pressure, preferably at atmospheric pressure, in the presence of a base. Preference is given to using perfluoro-n-alkanesulfonyl fluoride to obtain the perfluoro-n-alkanesulfonates of the formula I. As perfluoro-n-alkanesulfonyl fluorides, preference is given to using nonafluoro-n-butanesulfonyl fluoride or perfluoro-n-octanesulfonyl fluoride. Very particular preference is given to nonafluoro-n-butanesulfonyl fluoride.
The molar ratio of the respective phenol of the formula II to perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride is, in the process of the invention, generally from 1:2 to 1:20, preferably from 1:2 to 1:10. A ratio of from 1:2 to 1:5 is particularly preferred.
The reaction can be carried out in the presence of equimolar amounts of base and perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride or using an excess of the respective base.
Suitable bases for the process of the invention for preparing the compounds of the formula I are, for example, alkali metal carbonates and alkaline earth metal carbonates, for example sodium, potassium, magnesium or calcium carbonate. Particularly suitable bases are nitrogen heterocycles, amines or amidines. Preference is given to using nitrogen bases in which no H atoms are directly bound to an N atom. Preferred nitrogen bases are pyridines, pyrimidines, pyridazines, trialkylamines and dialkylarylamines, where the alkyl radicals in the trialkylamines and dialkylarylamines can be identical or different. Particular preference is given to imidazole, pyridine, p-dimethylaminopyridine, m-dimethylaminopyridine, o-dimethylaminopyridine, pyrimidine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, dimethylaniline, diethylaniline. Very particular preference is given to pyridine, imidazole, p-dimethylaminopyridine, m-dimethylaminopyridine, trimethylamine, triethylamine and dimethylaniline. It is also possible to use mixtures of the nitrogen bases mentioned.
The reaction time is generally from 0.1 to 24 hours, preferably from 0.2 to 6 hours.
The reaction of the phenol with perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride can be carried out in the melt or in solvents. Preference is given to carrying out the reaction in the presence of organic solvents.
Suitable solvents for the process for preparing the compounds of the formula I are halogenated hydrocarbons such as dichloromethane, trichloromethane, dichloroethylene or trichloroethylene, amides such as N,N-dimethylformamide or N-methylpyrrolidone or aromatic hydrocarbons such as benzene, toluene, xylenes, mesitylene, anisole, phenetole or tetrahydronaphthalene. It is also possible to use saturated hydrocarbons such as cyclohexane, n-hexane or n-octane, esters such as methyl acetate, ethyl acetate, propyl acetate or butyl acetate or ethers such as diethyl ether, methyl tert-butyl ether, tetrahydrofuran or dioxane. Preferred solvents for the process of the invention are dichloromethane, trichloromethane, dichloroethylene or trichloroethylene, N,N-dimethylformamide, N-methylpyrrolidone, benzene, toluene, in particular dichloromethane, trichloromethane, dichloroethylene or trichloroethylene.
Mixtures of the abovementioned solvents can likewise be used. It is likewise possible to use the abovementioned bases as solvents.
The amount of solvent is not critical; in general, from 10 to 10,000 g of solvent can be added per mole of phenol of the formula II to be reacted.
In general, essentially water-free solvents should be used.
Only when using appropriately large amounts of perfluoro-n-alkanesulfonyl fluoride, chloride or anhydride and the respective base can water present in the reaction mixture be neglected.
The compounds of the formula I can be obtained, for example, according to the following scheme: 
where A, B and n are as defined above.
The invention further provides for the use of the bis(perfluoro-n-alkanesulfonates) of the formula I as precursors for preparing chiral phosphine compounds of the formula III 
where A and B are as defined-above and
R2,R3 are, independently of one another, phenyl, 4-methylphenyl, 3-methylphenyl, 2-methylphenyl, 3,5-dimethylphenyl, 3,5-di-tert-butylphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 3,5-dimethoxyphenyl, cyclohexyl or cyclopentyl,
and also provides a process for preparing the compounds of the formula III, characterized in that the compounds of the formula I are reacted in the presence of a transition metal catalyst and a base either with phosphines of the formula IV 
or with zinc and phosphines of the formula V 
where R2 and R3 are as defined above.
The compounds of the formula III are used, in particular, as chiral ligands for transition metal catalysts which make it possible to carry out enantioselective reactions such as hydrogenations or C,C couplings.
The preferred meanings of the groups A and B given for the compounds of the formula I also apply to the compounds of the formulae II and III.
R2 and R3 are preferably, independently of one another, phenyl, 4-methylphenyl, 3-methylphenyl, 3,5-dimethylphenyl, 3,5-di-tert-butylphenyl or cyclohexyl. R2 and R3 
are particularly preferably phenyl. Compounds of the formula III in which R2 and R3 have the same meaning are very particularly preferred.
Particularly preferred compounds of the formula III which can be prepared using the compounds of the formula I are those of the component formulae III1-III16:
where R and R1 are as defined above.
The compounds of the formula III can be prepared by reacting the perfluoro-n-alkanesulfonates of the formula I, preferably in an organic solvent, with a phosphine of the formula IV at temperatures of from 20xc2x0 C. to 150xc2x0 C., preferably 30xc2x0-120xc2x0 C., in particular from 40xc2x0 to +100xc2x0 C., under superatmospheric or subatmospheric pressure, preferably at atmospheric pressure, in the presence of a base and a transition metal catalyst.
The compounds of the formula III can also be prepared by reacting the perfluoro-n-alkanesulfonates of the formula I, preferably in the absence of solvent, with a phosphine of the formula V at temperatures of from 20xc2x0 C. to 150xc2x0 C., preferably 30xc2x0-120xc2x0 C., in particular from 40xc2x0 to +100xc2x0 C., at superatmospheric or subatmospheric pressure, preferably at atmospheric pressure, in the presence of a base, zinc and a transition metal catalyst.
Zinc is preferably used in the form of a fine powder. The molar ratio of the respective perfluoro-n-alkanesulfonate of the formula I to zinc used is generally from 1:2 to 1:40, preferably from 1:2 to 1:20, in the process of the invention for preparing the compounds of the formula III. Particular preference is given to a ratio of from 1:2 to 1:10.
The molar ratio of the respective perfluoro-n-alkanesulfonate of the formula I to the phosphines of the formula IV or V is generally from 1:2 to 1:20, preferably from 1:2 to 1:10, in the process of the invention for preparing the compounds of the formula III. Particular preference is given to a ratio of from 1:2 to 1:5.
The molar ratio of the respective perfluoro-n-alkanesulfonate of the formula I to the base used is generally from 1:2 to 1:20, preferably from 1:2 to 1:15. Particular preference is given to a ratio of from 1:2 to 1:10.
The molar ratio of the respective perfluoro-n-alkanesulfonate of the formula I to the transition metal catalyst used is generally from 100:1 to 2:1, preferably from 50:1 to 5:1. Particular preference is given to a ratio of from 20:1 to 10:1.
As transition catalysts for the conversion of the compounds of the formula I into the phosphines of the formula III, preference is given to using nickel and palladium catalysts such as palladium acetate, PdCl2, PdCl2-bis(triphenylphosphine) or Pd-tetrakis(triphenylphosphine). Nickel catalysts are preferably used. Particular preference is given to NiCl2-bis(diphenyl)phosphinylmethane, -ethane, -propane or -butane, NiBr2, NiCl2, NiCl2-bis(diphenyl)phosphinylferrocene, NiCl2-bis(triphenylphosphine), Ni-tetrakis(triphenylphosphine), Ni-tetrakis(triphenyl phosphite) or Ni-dicarbonylbis(triphenylphosphine). Very particular preference is given to NiCl2, NiCl2-bis(diphenyl)phosphinylethane or NiCl2-bis(diphenyl)phosphinylpropane. The catalysts can also be formed in situ by adding the transition metal or transition metal salt and the corresponding ligand separately to the reaction mixture. It is likewise possible to add mixtures of transitional metal catalysts to the reaction mixture.
Suitable bases for the conversion of the compounds of the formula I into the phosphines of the formula III are, for example, alkali metal carbonates and alkaline earth metal carbonates, for example sodium, potassium, magnesium or calcium carbonate. Particularly suitable bases are nitrogen heterocycles, amines or amidines. Preference is given to using nitrogen bases in which no H atoms are bound directly to an N atom. Preferred nitrogen bases are pyridines, pyrimidines, pyridazines, trialkylamines, dialkylarylamines or DABCO (diazabicyclo[2.2.2]octane), where the alkyl radicals in the trialkylamines and dialkylarylamines can be identical or different. Particular preference is given to DABCO, imidazole, pyridine, p-dimethylaminopyridine, m-dimethylaminopyridine, o-dimethylaminopyridine, pyrimidine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, dimethylaniline, diethylaniline.
Very particular preference is given to DABCO, pyridine, imidazole, p-dimethylaminopyridine, m-dimethylaminopyridine, trimethylamine, triethylamine and dimethylaniline. It is also possible to use mixtures of the nitrogen bases mentioned.
The reaction time is generally from 1 hour to 6 days.
Preference is given to using polar solvents for the conversion of the compounds of the formula I into the phosphines of the formula III. Suitable solvents are, for example, amides such as N,N-dimethylformamide or N-methylpyrrolidone, sulfolane, sulfoxides such as dimethyl, diethyl or dibutyl sulfoxide, nitriles such as acetonitrile or propionitrile, esters such as methyl acetate or ethyl acetate or ethers such as tetrahydrofuran or dioxane or ketones such as acetone. Preferred solvents for the process of the invention are N,N-dimethylformamide, N-methylpyrrolidone, sulfolane, dimethyl sulfoxide or acetonitrile. Mixtures of the solvents mentioned can likewise be used. It is likewise possible to use the abovementioned nitrogen bases as solvents.
The amount of solvent is not critical; in general, from 10 to 10,000 g of solvent can be added per mole of perfluoro-n-alkanesulfonate to be reacted.
The compounds of the formula III can be obtained, for example, according to the following scheme: 
a) HPR2R3, base, NiCl2dppe
b) CIPR2R3, Zn, base, NiCl2,
where A, B, n and R2 and R3 are as defined above.
The formulae I, II and III include both the R and the S enantiomers of the compounds. Likewise, the mixtures of the enantiomers are encompassed by these formulae.
The compounds of the formulae II, IV and V required as starting materials are either known or can be prepared by methods known per se, as are described in the literature (e.g. in standard works such as Houben-Weyl, Methoden der Organischen Chemie, Georg-Thieme-Verlag, Stuttgart), under reaction conditions which are known and suitable for the specified reactions. Use can also be made here of variants which are known per se but are not described in more detail here.
Even without further embodiments, it is assumed that a person skilled in the art will be able to make very wide use of the above description. The preferred embodiments are therefore to be regarded merely as a descriptive, but in no way limiting, disclosure.